Electronic endoscope

Abstract

An electronic endoscope includes a solid-state image sensor disposed within the distal end of insertable portion thereof, a picture image processor disposed remote from the solid-state image sensor and a drive circuit for the solid-state image sensor. The electronic endoscope further includes a terminal resistor for impedance matching on input and/or output terminals of the solid-state image sensor within the distal end of the insertable portion thereof, so as to stabilize a signal associated with the solid-state image sensor and obtain a good picture.

What is claimed is: 
     
       1. An electronic endoscope having a solid-state image sensor disposed at the distal end of the insertable portion thereof, characterized in that a terminal resistor for impedance matching is disposed within said distal end, and   said terminal resistor is formed by a frame body of said distal end in which said solid-state image sensor is fixed.   
     
     
       2. An electronic endoscope according to claim 1 in which said frame body supports a lens for image pickup. 
     
     
       3. An electronic endoscope according to claim 2 in which said terminal resistor has a value such that an input and/or output impedance at the input and/or output terminal of said solid-state image sensor is nearly equal to an input and/or output characteristic impedance of an input signal line and/or a drive signal line of said image sensor. 
     
     
       4. An electronic endoscope according to claim 1 in which said terminal resistor has a value such that an input and/or output impedance at the input and/or output terminal of said solid-state image sensor is nearly equal to an input and/or output characteristic impedance of an input signal line and/or a drive signal line of said image sensor. 
     
     
       5. An electronic endoscope having a solid-state image sensor disposed at the distal end of the insertable portion thereof, characterized in that a terminal resistor for impedance matching is disposed within said distal end,   said terminal resistor is connected to the input and/or output terminals of said solid-state image sensor in parallel therewith,   said terminal resistor is formed by front and rear frame bodies which constitute a frame body of said distal end thereof and which are electrically separated into a plurality of parts on the input and output terminals of said solid-state image sensor.   
     
     
       6. An electronic endoscope according to claim 5 in which said terminal resistor has a value such that an input and/or output impedance at the input and/or output terminal of said solid-state image sensor is nearly equal to an input and/or output characteristic impedance of an input signal line and/or a drive signal line of said image sensor.